Excel Automation with vlookup and pivot

Hi Guys,

I have below requirement to automate Excel(more than 50K records). Kindly let me know the best way for fast execution.

1.) Insert 3 columns say A, B, C (A in position 12 and B, C at last)
2.) Column A should be filled by concatenating 2 columns within excel
3.) Column C should filled with default value after filtering a specific column say M
4.) Remove filter
5.) Column B should be filled using vlookup with another excel
6.) Create Pivot table within the excel to vlookup again with sheet 1 to fill unfilled Column B values

Please let me know the best way to achieve this. Whether to do the above with excel itself or with data table. Also share the activities for each step.

Thanks in advance